Southern sleeper shark

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Southern sleeper shark
Somniosus antarcticus.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Order: Squaliformes
Family: Somniosidae
Genus: Somniosus
Species:
S. antarcticus
Binomial name
Somniosus antarcticus
Whitley, 1939 [2]
Somniosus antarcticus distmap.png
Range (in blue)

The southern sleeper shark, or Whitley's sleeper shark (Somniosus antarcticus), is a deepwater benthopelagic sleeper shark of the family Somniosidae found in the southern and subantarctic extremes of the Atlantic, Indian and Pacific Oceans, and some northern reaches of the Antarctic oceans. [1] It has been recorded near the southernmost areas of South America (such as Tierra del Fuego and the Strait of Magellan), near South Africa, southern Australia, Tasmania and New Zealand, as well as more remote locations in the south-central Indian Ocean.

Contents

Taxonomy

It was formerly sometimes viewed as conspecific with either the Greenland shark (Somniosus microcephalus), or the Pacific sleeper shark (Somniosus pacificus). [3]

Habitat

A deepwater species, the southern sleeper shark is known to frequent waters around 400m (1312 feet) to as deep as 1100m (3608 feet). [1] [4]

Description

The southern sleeper shark's body length measures up to 4.4 m (14 ft). [4] This species differs from the Greenland shark (S. microcephalus) with the presence of additional rows of teeth in its lower jaw, a shorter interdorsal region, a more posterior first dorsal fin, and fewer precaudal vertebrae. Compared to both the Greenland and the Pacific sleeper shark (S. pacificus), the southern sleeper has lower dorsal fins, which the other two do not. [3]

Diet

The southern sleeper shark feeds primarily on cephalopods, especially squid — including the giant and colossal squids — and numerous fishes. Documented stomach contents of individual sleeper sharks have also, albeit infrequently, contained the remains of marine mammals or seabirds, possibly as a result of scavenging on sunken carcasses or whale falls. [1] Based on its generally sluggish nature and the comparative speed of its prey, it is thought to be an ambush predator. [1] A 3.6 m (12 ft) long female, caught off the coast of Chile, had a whole southern right whale dolphin in its stomach. The dogfish is sometimes taken as accidental bycatch in the orange roughy and Patagonian toothfish fisheries; whether or not this poses a threat to the species is currently unknown. [1]

Conservation status

In June 2018 the New Zealand Department of Conservation classified the southern sleeper shark as "Not Threatened" with the qualifiers "Data Poor" and "Uncertain whether Secure Overseas" under the New Zealand Threat Classification System. [5] The IUCN also does not regard it as threatened, noting a widespread distribution and no indication of a declining population, but believes it is not naturally abundant and that much more data and understanding of its population, interactions and biology is needed. [1]

Related Research Articles

<span class="mw-page-title-main">Pacific sleeper shark</span> Species of shark

The Pacific sleeper shark is a sleeper shark of the family Somniosidae, found in the North Pacific on continental shelves and slopes in Arctic and temperate waters between latitudes 70°N and 22°N and in at least two places in the western tropical Pacific near Palau and the Solomon Islands, from the surface to 2,000 metres (6,600 ft) deep. The first evidence of the sharks in the western tropical Pacific emerged from a National Geographic video taken near the Solomon Islands in 2015. Its length is up to 4.4 m (14 ft), although it could possibly reach lengths in excess of 7 m (23 ft).

<span class="mw-page-title-main">Southern right whale dolphin</span> Species of mammal

The southern right whale dolphin is a small and slender species of cetacean, found in cool waters of the Southern Hemisphere. It is one of two species of right whale dolphin. This genus is characterized by the lack of a dorsal fin. The other species, the northern right whale dolphin, is found in deep oceans of the Northern Hemisphere and has a different pigmentation pattern than the southern right whale dolphin.

<span class="mw-page-title-main">Greenland shark</span> Species of shark

The Greenland shark, also known as the gurry shark or grey shark, is a large shark of the family Somniosidae, closely related to the Pacific and southern sleeper sharks. Inhabiting the North Atlantic and Arctic Oceans, they are notable for their exceptional longevity, although they are poorly studied due to the depth and remoteness of their natural habitat.

<span class="mw-page-title-main">School shark</span> Species of shark

The school shark is a houndshark of the family Triakidae, and the only member of the genus Galeorhinus. Common names also include tope, tope shark, snapper shark, and soupfin shark. It is found worldwide in temperate seas at depths down to about 800 m (2,600 ft). It can grow to nearly 2 m long. It feeds both in midwater and near the seabed, and its reproduction is ovoviviparous. This shark is caught in fisheries for its flesh, its fins, and its liver, which has a very high vitamin A content. The IUCN has classified this species as critically endangered in its Red List of Threatened Species.

<span class="mw-page-title-main">Prickly shark</span> Species of shark

The prickly shark is one of the two species of sharks in the family Echinorhinidae, found in the Pacific Ocean over continental and insular shelves and slopes, and in submarine canyons. Bottom-dwelling in nature, it generally inhabits cool waters 100–650 m (330–2,130 ft) deep, but it also frequently enters shallower water in areas such as Monterey Bay off California. This stocky, dark-colored shark grows up to 4.0 m (13.1 ft) long, with two small dorsal fins positioned far back on its body and no anal fin. It is characterized by a dense covering of thorn-like dermal denticles, hence its common name.

<span class="mw-page-title-main">Sharpnose sevengill shark</span> Species of shark

The sharpnose sevengill shark, also known as one-finned shark, perlon shark, sevengill cow shark, sharpsnouted sevengill or slender sevengill, is a species of shark in the family Hexanchidae, and the only living species in the genus Heptranchias. Found almost circumglobally in deep water, it is one of the few species of sharks with seven pairs of gill slits as opposed to the usual five. The other shark species with seven gill slits is the broadnose sevengill shark. Though small, this shark is an active, voracious predator of invertebrates and fish. When caught, this species is notably defensive and will attempt to bite. It is of minor commercial importance.

<span class="mw-page-title-main">Longsnout dogfish</span> Species of shark

The longsnout dogfish is a little-known deepwater dogfish, found in the Atlantic and Indian Oceans from Namibia to Mozambique and in the South Pacific off southern Australia and New Zealand.

<span class="mw-page-title-main">Bareskin dogfish</span> Species of shark

The bareskin dogfish is a little-known, deepwater dogfish shark of the family Etmopteridae. This species is found in the western Pacific from southern Japan to western and southeastern Australia as well as in New Zealand waters.

<span class="mw-page-title-main">Kitefin shark</span> Species of shark

The kitefin shark or seal shark is a species of squaliform shark in the family Dalatiidae, and the type species in its genus. It is found sporadically around the world, usually close to the sea floor at depths of 200–600 m (660–1,970 ft). With a sizable oil-filled liver to maintain neutral buoyancy, this shark is able to cruise slowly through the water while expending little energy. The kitefin shark, the largest luminous vertebrate on record, has a slender body with a very short, blunt snout, large eyes, and thick lips. Its teeth are highly differentiated between the upper and lower jaws, with the upper teeth small and narrow and the lower teeth large, triangular, and serrated. Its typical length is 1.0–1.4 m (3.3–4.6 ft), though examples as long as 5.9 ft (180 cm) have been encountered.

<span class="mw-page-title-main">Somniosidae</span> Family of sharks

The Somniosidae are a family of sharks in the order Squaliformes, commonly known as sleeper sharks. The common name "sleeper shark" comes from their slow swimming, low activity level, and perceived non-aggressive nature.

<span class="mw-page-title-main">Longnose velvet dogfish</span> Species of shark

The longnose velvet dogfish is a sleeper shark of the family Somniosidae, found circumglobally in southern hemisphere subtropical seas, at depths of between 230 and 1,500 m. It reaches a length of 130 cm. It has a diet consisting of predominantly mesopelagic fishes and squids.

<span class="mw-page-title-main">Roughskin dogfish</span> Species of shark

The roughskin dogfish is a sleeper shark of the family Somniosidae, found around the world on continental shelves in tropical, subtropical and temperate seas, at depths of between 100 and 1,500 m. It reaches a length of 121 cm.

<i>Somniosus</i> Genus of sharks

Somniosus is a widely distributed genus of deepwater dogfish sharks in the family Somniosidae. Several members of the genus are believed to attain lengths up to 7 m (23 ft), thus ranking among the largest of sharks.

<span class="mw-page-title-main">Portuguese dogfish</span> Species of shark

The Portuguese dogfish or Portuguese shark, is a species of sleeper shark of the family Somniosidae. This globally distributed species has been reported down to a depth of 3,675 m (12,057 ft), making it the deepest-living shark known. It inhabits lower continental slopes and abyssal plains, usually staying near the bottom. Stocky and dark brown in color, the Portuguese dogfish can be distinguished from similar-looking species by the small spines in front of its dorsal fins. Its dermal denticles are also unusual, resembling the scales of a bony fish. This species typically reaches 0.9–1 m (3.0–3.3 ft) in length; sharks in the Mediterranean Sea are much smaller and have distinct depth and food preferences.

<span class="mw-page-title-main">Largespine velvet dogfish</span> Species of fish

The largespine velvet dogfish is a shark of the family Somniosidae, found on the lower continental slopes between latitudes 50°S and 54°S in the southeast Pacific Ocean from the Straits of Magellan, and the southwest Pacific from New Zealand, at depths of between 650 and 920 m. Its length is up to 68 cm. It was originally in the genus Centroscymnus because of the shape of its dermal denticles and dorsal fin spines but some argued to put this in the Scymnodon genus because of its shape of dermal denticles. While some wanted to allocate these in Centroscymnus because of the shape of its lower teeth but later it was allocated to a distinct genus called the Proscymnodon.

<span class="mw-page-title-main">Velvet dogfish</span> Species of shark

The velvet dogfish, the only member of the genus Zameus, is a small sleeper shark of the family Somniosidae, found around the world between latitudes 64°N and 48°S, from the surface to 2,000 m.

<span class="mw-page-title-main">Whitetail dogfish</span> Species of shark

The whitetail dogfish is a very rare sleeper shark of the family Somniosidae, found from the eastern Indian Ocean round southern Australia to New Zealand, at depths of between 150 and 500 m. Its length is up to 1.1 m.

<span class="mw-page-title-main">Smooth lanternshark</span> Species of shark

The smooth lanternshark or slender lanternshark is a species of dogfish shark in the family Etmopteridae, found widely in the Atlantic and Pacific Oceans. It inhabits benthic environments at a depth of 274–1,000 m (899–3,281 ft), and pelagic environments at a depth of 0–708 m (0–2,323 ft). The smooth lanternshark forms a species group with the larger blurred lanternshark, both of which are distinguished from other members of their family by small, irregularly arranged dermal denticles with a truncated shape. This species has a slender, dark brown body with an indistinct black band on the sides over the pelvic fins, and reaches 50 cm (20 in) in length. This slow-growing, ovoviviparous shark feeds on smaller squid, fishes, and fish eggs. Smooth lanternsharks are often caught as bycatch in eastern Atlantic and Japanese commercial fisheries. The International Union for Conservation of Nature (IUCN) has evaluated this species as of Least Concern because of its wide distribution and limited threats.

The frog shark is a very rare species of squaliform shark mainly found in deep water in the Pacific Ocean. It is in the sleeper shark family Somniosidae with the Greenland shark.

The Taiwan sleeper shark is a small sleeper shark from the western North Pacific Ocean around Taiwan. It is only known from a single adult specimen, a 1.34 m (4.4 ft) pregnant female with 33 embryos, which was caught in 2017.

References

  1. 1 2 3 4 5 6 7 Finucci, B. (2018). "Somniosus antarcticus". IUCN Red List of Threatened Species . 2018: e.T41857A68643703. doi: 10.2305/IUCN.UK.2018-2.RLTS.T41857A68643703.en . Retrieved 16 November 2021.
  2. Whitley, Gilbert P. (1939). "Taxonomic Notes on Sharks and Rays". The Australian Zoologist. 9 (3): 242.
  3. 1 2 Yano, Kazunari; Stevens, John D.; Compagno, Leonard J. V. (2004). "A review of the systematics of the sleeper shark genus Somniosus with redescriptions of Somniosus (Somniosus) antarcticus and Somniosus (Rhinoscymnus) longus (Squaliformes: Somniosidae)". Ichthyological Research. 51 (4): 360–73. Bibcode:2004IchtR..51..360Y. doi:10.1007/s10228-004-0244-4. S2CID   38054192.
  4. 1 2 Froese, Rainer; Pauly, Daniel (eds.). "Somniosus antarcticus". FishBase . February 2012 version.
  5. Duffy, Clinton A. J.; Francis, Malcolm; Dunn, M. R.; Finucci, Brit; Ford, Richard; Hitchmough, Rod; Rolfe, Jeremy (2018). Conservation status of New Zealand chondrichthyans (chimaeras, sharks and rays), 2016 (PDF). Wellington, New Zealand: Department of Conservation. p. 11. ISBN   9781988514628. OCLC   1042901090.